Method of recovering metals by electrolysis.



No. 697,83I. Patented Apr. I5, |902.

H. A. FHASCH.

METHOD 0F BECVERING METALS BY ELECTBOLYSIS.

(Application led Mar. 7, 1901.)

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HANS A. FRASCH, OF HAMILTON, CANADA.

METHOD OF RECOVERING METALS BY ELECTROLYSIS.

srncrrrcnrron forming part of Letters'ratent No. 697,831, dated Apri'i 15, 1962. Application iiled March 7, 1901. Serial No, 50,254- (No specimeusi) To @ZZ whom it may concern:

Beit known that I, HANS A. FRASCH, a citizen of the United States, residing at Hamilton, in the county of Wentworth and Province of Ontario, Canada, have invented a certain new and useful Improvement in Methods of Recovering Metals by Electrolysis, of which the following is a full, clear, and exact description.

This invention relates to the recovery of metals by electrolyzing an ,ammoniacal solution of those metals whose hydroxids are soluble in ammonia, and more particularly to the recovery of nickel and copper from ammoniacal solutions.

I am aware that the recovery of metals froml ammoniated metallic solutions is old; but in the methods heretofore practiced either insoluble anodes are used or if soluble anodes are used they are composed of the same metal as the one in the electrolyte, and after the metal contained in the solution has been re moved there results a solution of sulfate or chlorid of ammonia, according to whatever ammonium salt has been electrolyzed, so that it is necessary to recover the free ammonia from these solutions by distillation in order to allow the electrolyte to be resaturated. To do away with the necessity of this redistillation of the ammonia, I electrolyze the solution of copper or nickel ammonium chlorid or sulfatein presence of a soluble anode, and thereby form at the anode the sulfate or chlorid of the metal of which the anode is composed, while the metal contained originally in the electrolyte is deposited upon the cathode, and at the same time the ammonia is set free at the cathode, remaining in solution in free state, so that the same electrolyte can be resaturated with fresh metal and used over again.

I am aware that nickel is deposited by electrolysis from ammoniacal solutions in presence of nickel anodes, and a similar process has been applied to copper; but in this praetice the anode has to be composed of the sameA metal as is contained in the electrolyte, as otherwise the electrolyte would become contaminated with the metals contained in the anode. My invention permits the use of any metal for the anode without contaminating the electrolyte of the cathode, so that, for instance, my anode may consist of copper-nickel matte orore or other-material containingamixture of iron, copper, nickel, and other metals, and whileI deposit nickel from an ammoniacal solution at the cathode I form at the anode the sulfate or chlorid, as the case may be, of all the metals contained in the anode.

To carry out my invention, I prefer vto employ the apparatus described in my Patent No. 669,441, dated March 5, 1901; but I do not limit my invention to the use of this or any particular apparatus.

For illustration I will describe my process as carried out in the apparatus above mentioned for the recovery of nickel from nickelammonium chlorid as obtained by the invention describedin my Patent No. 669,89),dated March 12, 1901.

In the accompanying drawings, illustrating an apparatus which may be employed in carrying out myV invention, and in Which like parts are correspondingly designated, Figure l isa longitudinal section, and Fig. 2 is a top plan View.

For an anode a I use copper-nickel matte in comminuted state spread over the bottom of the vessel b, conducting the electric current thereto by means of suitable rods or bars c, those extending inside of the vessel preferably being of carbon because of its durability. This anode is covered with sand or any other granular electrically and chemically inert substance forming a permeable diaphragm d. The vessel is then illed to the top of the sand with a solution of sodium chlorid, preferably of about 20 Baume in strength. The remaining space of the vessel above the diaphragm is supplied with a solution of nickel-ammonium chlorid containing an eX- cess of ammonia, or I may use a solution of the normal nickel-ammonium chlorid, adding thereto free ammonia until the latter is in eX- cess. the diaphragm, and they may consist of any suitable metal, in this instance preferably nickel, and the whole is then subjected to an electric current of proper density. The nickel thereby is precipitated in metallic form upon the cathodes, while the chlorin in chemical combination with the ammonia and nickel lis liberated at the anode, there forming the chlorids of copper, nickel, iron, and whatever The cathodes e are suspended above IOG metals are contained in the anode. This chlorid solution may be continuously or periodically removed from the anode-section of the apparatus below the diaphragm by displacement with fresh solution of sodium chlorid or any other solvent supplied through pipe The ammonia liberated at the cathode by the removal of the chlorin remains in solution in the cathode electrolyte, and electrolysis may be conducted until the last trace of nickel has been removed from the cathode electrolyte, so that only a solution of free ammonia remains, which can then be used over again for the production of fresh nickelammonium chlorid without the necessity of distillation. Circulation of the electrolyte may be secured by means of pipesfand g and the interposed siphon, pump, or other apparatus h.

In applying the process the cathode electrolyte, consisting of a solution of an ammonium double salt bearing the metal to be deposited, is circulated above the diaphragm d by means of the pipes g, the anode-section below the diaphragm having been irst supplied With a solution of sodium chlorid. The electric current being passed between the cathode and the anode, the metal contained in the cathode electrolyte is deposited upon the cathode, While the halogen or acid radical contained in the cathode electrolyte is transferred to and chemically bound by the metals represented in the anode, forming the corresponding metal salts. The salt brine in the anode section dissolves the metallic salts formed there and is then displaced by a fresh supply of salt brine introduced through pipe f at one end, the concentrated metallic solution being drawn oi through a similar pipe at the other end. The circulation of the two electrolytes above and below the diaphragm may be continuous or periodical. I prefer to maintain a continuous circulation through the cathode-compartment, removing the metallic solution from the anode-compartment periodically whenever it has reached any desired degree of concentration. Thus I may subject an electrolyte consisting of a solution of nickelammonium chlorid in the cathode-compartment to an electric current, the anode-compartment being charged with zinc ore, and deposit metallic nickel upon the cathode,while simultaneously producing a solution of zinc chlorid in the anode without contaminating either of the electrolytes with the metals contained in the other.

What I claim isl. The process of recovering metals by electrolysis, which consists in electrolyzing a double salt of ammonia and metals whose hydroxids are soluble in ammonia, in presence of a soluble anode and an anode electrolyte (anolyte) containing metals different from the one contained in the cathode electrolyte (catholyte) but free from ammonia.

2. The method of electrolyzin g a double salt .of ammonia and metals whose hydroxids are soluble in ammonia, consisting of-electrolyzing a solution of an ammonium double salt containing metal in presence of an anode capable of combining with the acid or halogen radicals contained in the ammonium double salt, and having constituents different from the contents of the electrolyte.

3. The method of recovering ammonia from an electrolyte composed of an ammonium double salt, consisting in electrolyzin g a solution of an ammonium double salt containing metal in presence of a suitable cathode, and an anode capable of binding the acid or halogen radical of the ammonium salt, the cathode and anode being separated by a suitable diaphragm, depositing the metal contained in the solution upon the cathode, and binding the acid or halogen radical to the substance of the anode, keeping the ammonia in solution in the cathode electrolyte.

4. The method of recovering nickel from a nickel-ammonium salt, consisting in supplying an electrolytic bath with an anode composedl of a metal-bearing substance in comminuted form, covering it with a chemically and electrically inert permeable substance above which suitable cathodes are arranged, supplying the anode With a solution capable of dissolving the metallic salts there formed, supplying the cathode with a solution of the nickel-ammonium salt,subj ectin g it to an electric current, depositing the nickel upon the cathodes, and displacing the metallic solution at the anode by a fresh supply of solvent,keep ing the ammonia in solution in the cathode electrolyte.

5. The process of recovering nickel by electrolysis, which consists in supplying a cathode with a solution yof nickel-ammonium chlorid containing an excess of ammonia, and supplying a soluble anode consisting of different metals with a solution of sodium chlorid, separating the two solutions by means of a permeable diaphragm, and by means of an electric current precipitating the nickel in mei tallic form upon the cathode, and forming at the anode a solution of the chlorids of the various metals contained in the anode, substantially as described.

6. The process of recovering nickel by electrolysis, which consists in supplying a cathode with a solution of nickel-ammomium chlorid containing an excess of ammonia. and supplying a soluble anode consisting of dii'-l ferent metals with a solution of sodium chlorid, separating the two solutions by means of a horizontal permeable diaphragm, and by means of an electric current precipitating the nickel in metallic form upon the cathode, forming at the anode a solution of the chlorids of the various metals contained in the anode, and displacing the chlorid solution from below the diaphragm by addition of fresh sodium-chlorid solution.

7. The process of recovering nickel by electrolysis, which consists in supplying a cathode with a solution of nickel-ammonium chloof an electric current precipitating the nickel` in metallic form upon the cathode, forming at the anode a solution of the chlorids of the Various metals contained in the anode, displacing the chlorid solution from below the diaphragm by addition of fresh sodium-chlorid solution, and further electrolyzing the cathode solution until the last trace of nickel has been removed.

8. The process of recovering nickel by electrolysis, which consists in supplying a cathode with a solution of nickel-ammonium chlorid containing an excess of ammonia, and supplying a soluble anode consisting of different metals with a solution of sodium chlorid, separating the two solutions by means of a horizontal permeable diaphragm, and by means of an electric current precipitating the nickel in metallic form upon the cathode, forming at the anode a solution of the chloride of the various metals containedin the anode, displacing the chlorid solution from below the diaphragm by addition of fresh sodium-chlorid solution, and further electrolyzing the cathode solution until the last trace of nickel has been removed from the cathode electrolyte, and utilizing the remaining solution of free ammonia for the production of fresh nickel-ammonium chlorid.

In testimony whereof I have hereunto set myhand this 25th dayof February, A. D. 1901.

HANS A. FRASCH. Witnesses:

WILLIAM E. WOODRUFF, W. J. DEVINE. 

